The Battle of Yorktown in 1781 was the last major battle of the Revolutionary War. British General Lord Cornwallis camped his forces at Yorktown, a river port near Chesapeake Bay. With help from French allies, General George Washington trapped the British forces and laid siege to Yorktown. After failed attempts to escape across the York River, Cornwallis surrendered, marking a major victory for the Americans and effectively ending the Revolutionary War.